1. Field of the Invention
The present invention pertains to an improved infrared detector system capable of detecting an intruder upon reception of emitted infrared energy from his body. More particularly, the present invention provides an improved optical reflection system and circuit for processing the reflected energy to provide improved sensitivity and eliminate false alarms.
2. Description of the Prior Art
Infrared detection systems are well known in the prior art and a number of alternative systems are available commercially. Frequent problems have occurred with regard to the sensitivity of infrared systems and their ability to discriminate between actual human intruders and various changes in ambient background conditions. As a general rule, infrared sensors detect a change in IR radiation, and it is frequently necessary in the prior art for the target area to be relatively temperature stable. Sudden changes in room temperature, incident light, and room convection currents can cause false alarms. The prior art has also attempted to increase the scan range of the infrared detectors, both to maintain sensitivity and to lower manufacturing costs by preventing duplication of expensive component parts. Problems, however, have occurred in loss of sensitivity with extended scan ranges.
The following examples of patent literature are provided to disclose both the background of the present invention and prior art detection systems in this field; U.S. Pat. No. 3,036,219, U.S. Pat. No. 3,475,608, U.S. Pat. No. 3,480,775, U.S. Pat. No. 3,493,953, U.S. Pat. No. 3,524,180, U.S. Pat. No. 3,631,434, U.S. Pat. No. 3,703,718, U.S. Pat. No. 3,839,640, U.S. Pat. No. 3,928,843, and U.S. Pat. No. 3,958,118.
The prior art is still seeking to provide an optimized infrared passive detection system that can be manufactured at relatively economical cost while improving both the sensitivity of the system and the elimination of spurious alarm signals.